How do I change my Casio twin sensor alti thermo watch from 24 hour to 12 hour format?

To Toggle between 12-hour and 24-hour timekeeping:

In the Timekeeping Mode (regular watch display), press the lower right-hand button to toggle between 12 and 24 hour timekeeping.

You can download the manual from the link below. The information you requested can be found on page 2 (left column).
http://support.casio.com/en/manual/009/qw3768.pdf

Was this problem answered? If yes, can somebody tell me how. My Casio LA670W is in 24hr format and I want it back on 12hr format. My watch have 3 buttons only. Mode, Start-Stop and Timer

Try this:-

First set the watch to 24 hour format rather than 12 hour format.

Hi Harry,

Your Module number is 2271.
1. To set the time, press and hold button A (left top) until Seconds digits start to flash.
2. Press button D (lower left) to move flashing in the following sequence to change other setting:
Seconds >> Hour >> Minutes >> 12/24 Hour Format >> Year >> Month >> Day >> (Then back to Seconds)
3. While a setting is flashing, use E (+) (bottom right) and B (-) (top right) to change it.
Note: When in the 12/24 Hour Mode, use E and B to toggle between 12-Hour and 24-Hour Mode.
4. Press buton A to exit setting screen.
Your time should now be set.

You may also download a manual for watch/Module number:
http://pathfinder.casio.com/resource/manuals/module_2271.pdf

This should give you all the info you need to operate all the functions of your watch. Thanks.

Regards, Bill

I've been giving this advice to many other Casio uowners, but it much quicker and easier, if you will take your four-digit caliber number from the watch back, go to this link, and enter it there for a complete PDF file about your watch.

http://world.casio.com/wat/download/en/manual/

Good luck! Bill

mcdevito75 here, Here is Casio"s contact info, 800-435-7732 hope they can help.

Click on my profile (escapement), then click on Tips and Tricks. There you will find links to all watch manuals. Rate me, please .

Follow this link and find out what you want:

http://world.casio.com/wat/download/en/manual/

Rate me, please.